public class MainClass {
    public static void main(String[] args){
        System.out.println("你好，只需编译我");
        A a = new A();
        a.fA();
        B b = new B();
        b.fB();
        C c = new C();
        c.fC();
    }
}
class A {
    void fA() {
        System.out.println("I am A");
    }
}
class B {
    void fB() {
        System.out.println("I am B");
    }
}
class C {
    void fC(){
        System.out.println("I am C");
    }
}
